1. Field of the Invention
The present invention is broadly concerned with an improved metal roof panel attachment system which produces a finished roof surface having an overall smooth, planar configuration. More particularly it is concerned with a system in which adjacent planar panels are attached to secondary support members which form a recessed joint incorporating a concealed drainage channel.
2. Description of the Prior Art
Prior art panel attachment systems for vertical, sloped or horizontal surfaces employed standing seams secured against moisture penetration by battens, or interlocking, so called "flat" seams secured by sealing or soldering. Both methods produce an upstanding seam which extends outwardly from the surfaces of the panels and thus, the overall finished appearance of surfaces incorporating such seams is not smooth and flat.
In such prior art systems the panels are held in place by clips or fasteners, or the adjacent panels are interlocked into fastened seams. The upstanding seams are secured by crimping, interlocking, or soldering to prevent penetration of moisture to the back sides of the panels and the underlying roof or wall surface. These attachment points are rigidly fixed, and consequently thermal expansion and contraction stresses accumulate around these points, causing wear. Moreover, the strength of such panel systems is dependent upon the secondary clips or fasteners.
Previous interlocking "flat" seams depend on a gasket or sealant as the main barrier to moisture infiltration. Such seams are subject to deterioration caused by exposure to temperature extremes and ultraviolet radiation, in addition to wear caused by thermal movements of the panels.
Installation of panels using previous attachment systems requires fastening the panels into fixed positions with exposed fasteners or clips, interlocking the seams by aligning and engaging battens over the clips, or by crimping or secondary machine seaming. Skilled labor and specialized crimping and seaming machinery are required for such installation. Single panels damaged during installation or thereafter cannot easily be removed without affecting adjacent panels.